I must have been otherwise engaged at the time.
3 seconds sound clip from the Shadowlands movie soundboard.
You can hear this line at 00:18:22.527 in the Blu-ray version of the movie.
Quote context
[...]
- I'm not. I was an atheist once.
- You?
- So we're both lapsed atheists?
- Yes, but I was never a communist.- Why not?
- What do you mean, Why not, Mrs. Gresham?
- I must have been otherwise engaged at the time.
- There's a world worth saving.
- I can't say I've ever risen early enough to hear them.
- Oh, why not? I mean, it sounds wonderful.
- Well, I don't really go in for seeing the sights.
- Oh! So what do you do? Just walk around with your eyes shut?
[...]